Asphalt production



ug- 31, 1954 H. s. GOODWIN ASPHALT PRODUCTION Filed Nov. 30. 1951 mi iAIL Patented Aug. 31, 1954 UNITED STATES PATENT DFFICE ASPHALTPRODUCTION Henry S. Goodwin, Aruba, Netherlands West Indies, assigner toStandard Oil Development Company, a corporation of Delaware ApplicationNovember 30, 1951, Serial No. 259,133

3 Claims.

This invention concerns a novel process for producing asphalts frombituminous materials obtained from crude petroleum oils. The processconcerns particular blending and reduction procedures to provide a widevariety of asphalt products, having desirable properties, in a manner topermit production of optimum yields of high quality asphalt products. Inparticular this invention permits successful blending of asphalticmaterials to provide homogeneous asphalt products which have heretoforebeen blended to provide heterogeneous asphalt products.

A number of techniques are now known for producing asphalts of varyingphysical properties from petroleum crude oils, or fractions thereof,which contain asphaltic materials. For example, a variety of processeshave been suggested for producing asphalts by reduction of petroleumfractions containing asphalts, by oxidation of asphaltic materials, andby various blending operations. Limitations of presently known asphaltprocessing operations, however, limit the range of different propertiesobtainable in the nal asphalt products. Again, combinations ofproperties such as the susceptibility factor, the flash point, and theductility of the final asphalt product are limited by the pres-` entprocessing techniques.

In this connection, for example, the temperature susceptibilitycharacteristics of asphalts obtained by the reduction of asphalticmaterials found in a given petroleum oil are in many cases lessdesirable than might be required. It is a principal objective of thisinvention therefore, to permit obtaining asphalt susceptibilitycharacteristics which are substantially improved over those obtainableby presently known processes.

The process of this invention by means of which these and otherobjectives are attained is a basically new treating process sequence.The process permits production of asphalts of improved physicalproperties and provides a relatively limitless range of combinations ofphysical properties for asphalts from a given crude source. The processentails the blending of particular types of asphaltic materials followedby the reduction of these materials to a desired consistency. Uniquelyit has been found that by these simple processing steps of blending andreducing, it is possible to obtain the indicated advantages.

The nature of this invention can be well understood by reference to anasphalt property generally designated as homogeneity. This propertyconcerns what has been referred to as 2 'the complete amalgamation ofthe asphalti constituents present in an asphaltic product.Heterogeneity, as opposed to homogeneity, refers to the imperfectblending of bituminous constituents, and is usually indicative of thepresence of unsaturated compounds. While heterogeneity of asphaltproducts may be tolerated for certain applications, ingeneralhomogeneous asphalt products are preferred, and are required for manyapplications. For example, paving grade asphalt products must behomogeneous in nature to meet specification limitations and to Supplythe requirements of actual use. A heterogeneous paving asphalt willexhibit poor aging and weathering characteristics.v

Some heterogeneous asphaltic materials have very desirable propertieswhich are not ordinarily obtainable in combination with other desirableproperties found in homogeneous asphalts. Blending of heterogeneous withhomogeneous asphaltic materials to obtain such combinations ofproperties has heretofore produced heterogeneous products. By means ofthe process described in this patent it is now possible to blendheterogeneous with homogeneous asphaltic materials, and obtain thedesired combinations of properties, and at the same time producehomogeneous asphalts.

This is accomplished by a simple two-step processing sequence,necessitating the blending of the asphaltic materials to be combined,followed by a reducing operation conducted to drive off a distillateportion of the blended asphaltic materials. In some manner which is notpresently understood, the reducing step is operative to convert whatwould otherwise be a heterogeneous product to a homogeneous asphalt.This makes possible the production of homogeneous asphalt productshaving heretofore unobtainable properties and combinations of propertiesfrom an originalcrude source.

In the practical application of this invention, the two materials to beinitially combined must be particularly chosen. The materials maygenerally be designated as a heterogeneous asphaltic material generallyhaving a low susceptibility factor and a homogeneous asphaltic materialgenerally having a higher susceptibility factor. As exemplary of thefirst class of compounds, reference may be made to tars, particularlytars which have been derived from mild petroleum cracking operations onasphaltic crudes, and to oxidized asphalts such as derived fromasphaltic reduced crude oils. Such asphaltic materials, that is, suchtars and oxidized asphalts are char- 'distillation column 3.

acterized by susceptibility lfactors lower than about 3.3. In thisconnection, and as used herein, susceptibility factor may be defined asthe ratio of the penetration of the asphaltic material at 25 C. per 100g. per 5 seconds to the penetration of the asphaltic material at C. per200 g. per 60 seconds. As stated, these asphaltic materials are normallyheterogeneous as determined, for example, by what is known-as theOlienses test.

The other of the two asphaltic materials to be combined may be definedas a low softening point reduced asphalt obtained from an asphalticcrude oil or reduced crude oil. Such an asphaltic material is normallyhomogeneous and possesses a relatively higher susceptibility factor,extending up to about 14. The invention is of particular applicationwhen employing a reduced asphalt having a susceptibility factor of about3.3 to 6.

In the nrst step of the process therefore, a heterogeneous asphalticmaterial, such as a tar or oxidized asphalt, is mixed with a homogeneousasphaltic material such as a reduced asphaltic crude or asphalt. It iscritical, in this step of the process, that particular proportions ofthese two asphaltic materials be combined. For the purposes of thisinvention it has been found that not more tha-n about 35% of theheterogeneous material may be combined with the homogeneous material.For some reason, if more than about 35% of the heterogeneous material beincluded in the combination, it is not always possible to obtain a iinalasphalt product which is homogeneous. It has been found that, in fact,from 15 to 25% of the heterogeneous material is best blended with thehomogeneous material. On the mixing of these two asphaltic materials, aheterogeneous asphaltic material is obtained. This heterogeneousmaterial is then reduced to a desired consistency so as to obtain a. nalproduct in yields of not more than about 97% based on the heterogeneousmixture. The reduction may be carried out by means known to the art, butwill generally and preferably entail distillation of the asphalticmaterial under reduced pressures to secure the removal of about 3% ormore of the more volatile constituents. Depending upon the asphalticmaterials originally combined and the desired properties of the finalasphalt product, as much as 50% or more of the volatile constituents canbe removed in this manner. It is a peculiarity of this processingoperation and, in fact, a basic discovery that this reduction isoperative to render a homogeneous asphalt product. In general, thisasphalt product will be characterized by particular asphalt propertiesand combinations of asphalt properties not otherwise obtainable by theprocessing of asphaltic materials from a given crude oil. In securingthis result it is critical that at least some elimination of the morevolatile constituents present be obtained which, as indicated, must bemore than about 3%.

The process of this invention may be readily understood by reference tothe accompanying drawing which diagrammatically illustrates a preferredembodiment of the invention. A petroleum crude oil may be employed as afeed material to be passed through. line I, heat exchanger 2 and apre-heating furnace for introduction to Distillation column Il maycomprise a conventional type of still for the fractionation of a crudeoil into a variety of petroleum fractions including a reduced crude oilfraction to be removed from the still 4 through bot- `cnude oilisreduced in this manner, and, in fact,

may, if desired, incorporate the entire crude oil provided that thecrude contain asphaltic materials. This crude or reduced crude oil thusprovides an asphaltic material of a homogeneous character having a lowsoftening point and characterized by a susceptibility factor which mayextend up to vabout 14. In other words, the temperature susceptibilityof this reduced asphaltic material, as derived from a crude oil, may bepoor in nature. This asphaltic material withdrawn from still 4 throughline 5 is then split into two streams, 6 and '1. The stream of line @maybe directly introduced to blendingapparatus I I, wherein it is mixedwith a higher softening point, heterogeneous asphaltic materialintroduced to the blender through line 9. The

.higher softening point blending component may constitute a petroleumtar or oxidized asphalt.

Again, this blending component may constitute aheterogeneous asphalticmaterial which maybe derived fromthe original crude oil. For example,the stream of line "I may be subjected to air blowing or cracking inzone 8 to kprovide an oxidized asphalt or tar of this character. Thematerial is characterized by a low susceptibility factor generally lessthan about 3.3. It is necessary to heat the tar or the oxidized asphaltto an elevated 'temperature of about 20T-450 F., to reduce viscositysufficiently to permit blending. For this purpose the material may bepassed through a pre-heating furnace I5 prior to introduction to blenderII.

The two asphaltic materials introduced to blending apparatus II aremaintained at a suflciently hightemperature to permit ready mixing underthe iniiuence of agitation appliedas by means of the propeller stirrersillustrated in the blending apparatus I I. As a result of this blendingoperation, a product may be withdrawn through line I2 constituting aheterogeneous mixture of the reduced crudeasphaltic material and thehigher softening point blending component. 'Thismixture is passedthrough a preheater and is then introduced to a vacuum iiash tower. I3where a portion of the lighter fractions are removed through overheadline I4 and/or one or more side stream withdrawals. The final product isthen withdrawn as a bottoms product from the ash tower through line I5.The nal asphaltic product comprises a homogeneous Vasphaltic blend ofthe two combined asphaltic materials.

As an example of the benefits of this invention, reference is made tothe accompanying Table I. The rst column of this table indicates typicalasphalticv properties obtainable by reduction of a crude oil. The secondand third columns of Table I show the results obtainable by the processof this invention in which a reduced crude asphaltc material is blendedwith a reduced cracked tar` and an oxidized asphalt respectively. Itwill be observed that columns 2 and 3 embody ythis invention and produceasphalts having substantially better susceptibility factors,` forasphalts `having the same softening point, than obtainable by straightreduction of asphaltic bottoms. 4The asphalts of columns 2 and 3 wouldbe substantially betterthan the `asphalt of column'l for applicationssuch as roofing and road paving due to the lower susceptibility totemperature changes. In the embodiment of the invention illustrated bycolumns 2 and 3 of Table I, the remaining asphalt properties aresubstantially the same as those obtained by the conventional reductionprocess illustrated in column 1.

TABLE I for the production of asphalts. According to this process, twoparticular asphaltic materials are blended in particular proportions andsubjected to at least some reduction. As a result, the originalmaterials combined are converted to the form of a homogeneous asphaltproduct having Data illustrating the improved susceptibilitycharacteristics of asphalts` produced by the invention, as compared tothe conventional reduction process Method oi Producing Composi-Reduction to tion of Feed Stock Grade Reduction to Grade of Blended FeedSt k Lagunillas Reduced Crude e Aruba Soft Bitumen b 17o/180 S. P.Oxidized Aspha Specific Gravity at 85 F Flash, C. O. C., SofteningPoint, F-..

Pen. at32 F Ductility at 77 F I nsol. in 86 Naphtha, Percent SOLinCSz,Percent 99.9 99.8 99.9.

Olienses Test Homogeneous. Homogeneous- Homogeneous. SusceptibilityFactor (Pen. at 4.0 3.4 2.8.

C./Pen. 0 0.).

91.0% heavy crude bottoms (homogeneous).

b 165/l75 S. P. reduced cracked tar, 167 S. P., 19 pen. at 77 F., and9pen. at 32 F.

( heterogeneous).

17o/180 S. P. oxidized asphalt, 176 S. P., 17pen. at 77 F., and 7 pen.at 32 F.

(heterogeneous).

Referring now to the accompanying Table II, further results areillustrated for the blending of an asphaltic reduced crude bottoms witha reduced cracked tar and with an oxidized asphalt. The proceduresconducted to obtain the asphalts indicated in the second and. thirdcolumn of Table II are identied in the table and lembody the process ofthis invention. Comparing the asphalt inspections of Table II to theiirst column of Table I, it will be observed that in all cases theresulting asphalts had substantially better (lower) susceptibilityfactors. With reference to the other asphalt properties identified, thatisy ash point, ductility, etc., the data indicates the variety inasphaltic properties which can be obtained by varying the nature andproportions of the constituents blended and reduced in accordance withthis invention.

TABLE II properties substantially better than obtainable by straightreduction, oxidation, or blending of the feed materials by conventionalprocessing. Again, by varying the proportions and nature of asphalticmaterials treated in accordance with this process, a wide range ofasphaltic properties may be obtained.

What is claimed is:

1. A process for producing a homogeneous asphalt blend by thecombination of two asphalte, one of which is heterogeneous whichcomprises the sole treating steps of: mixing a first heterogeneousasphalt selected from the class consisting of tars derived by crackingasphaltic crude oils and oxidized asphalts, characterized by asusceptibility factor lower than about 3.3, and a second homogeneousasphalt derived from an asphaltic crude oil by reduction, characterizedby Data illustrating the improved ductility and flashpointcharacteristics of asphalte produced by the invention as compared to theconventional direct blending process Method ci Producing Composi-Blending to Reduction to Grade of Blended tion of Blend or Feed StockGrade Feed Stock Percent Lagunillas Red. Crude... 44.0 e 851). PercentAruba Soft Bitumen v 56.0 Percent Oxidized Asphalt d 15 0 SpecificGravity at 85 F 1.023. Flash, o. o. 0., F 5 595. softening Point, F.130. Pen. at 77 F 55. Pen. at 32 F 26. Ductility at 77 F 100+. Insol. in86 Naphtha, Percent. 21.0. Sol. in CS2, Percent.-- 99.8... 99.8.. 99.8.Ohenses 'I est Heterogeneous. Homogeneous. Homogeneous. SusceptlbilityFactor (Pen. at 25 2.3 2.6 2.1.

CJPen. at 0 0.).

e 86 S. P. asphalt ux (59% crude bottoms) (homogeneous). b 91% reducedcrude bottoms (homogeneous). 16S/175 S. P. reduced cracked tar(heterogeneous).

d l/180 S. P. oxidized asphalt produced by the oxidation of binder Casphalt (heterogeneous).

As brought out herein, the process of this invention is a basically newand versatile process a susceptibility factor higher than about 3.3,said mixture including not more than about 35% of 2,687,989 7' 8 thesaid rst asphalt and forming a heterogeneous said second asphalt has asusceptibility factor of asphalt composition, and thereafter reducingthe about 3.3 to 6. said mixture by removal of at least 3% of the morevolatile constituents of the mixture, whereby a References Cited in thefile 0f thS patent fn .l homogeneous as halt com ositon i ob- 5 died p ps UNITED STATES PATENTS 2. The process dened by claim 1 in Which theNumber Name Date said lst asphalt comprises about 15 to 25% of 2,220,714Hersberger Nov. 5, 1940 said mixture. 2,317,150 Lovell et al. Apr. 20,1943 3. The process dened by claim 1 in which the l0

1. A PROCESS FOR PRODUCING A HOMOGENEOUS ASPHALT BLEND BY THECOMBINATION OF TWO ASPHALTS, ONE OF WHICH IS HETEROGENEOUS WHICHCOMPRISES THE SOLE TREATING STEPS OF: MIXING A FIRST HETEROGENEOUSASPHALT SELECTED FROM THE CLASS CONSISTING OF TARS DERIVED BY CRACKINGASPHALTIC CRUDE OILS AND OXIDIZED ASPHALTS, CHARACTERIZED BY ASUSCEPTIBILITY FACTOR LOWER THAN ABOUT 3.3, AND A SECOND HOMOGENEOUSASPHALT DERIVED FROM AN ASPHALTIC CRUDE OIL BY REDUCTION, CHARACTERIZEDBY A SUSCEPTIBILITY FACTOR HIGHER THAN ABOUT 3.3, SAID MIXTURE INCLUDINGNOT MORE THAN ABOUT 35% OF THE SAID FIRST ASPHALT AND FORMING AHETEROGENEOUS ASPHALT COMPOSITION, AND THEREAFTER REDUCING THE SAIDMIXTURE BY REMOVAL OF AT LEAST 3% OF THE MORE VOLATILE CONSTITUENTS OFTHE MIXTURE, WHEREBY A FINAL HOMOGENEOUS ASPHALT COMPOSITION ISOBTAINED.